Self-tracking: the people turning their bodies into medical labs

As well as helping to track finances and organise social lives, smartphones are encouraging some people to monitor their health and wellbeing. By recording and logging data about their lifestyles, these 'self-trackers' aim to better understand problems ranging from snoring to depression

Within the first five minutes I spend with Ian Clements, I learn the following. He is 76 years old and he always thought it was his destiny to be the oldest man on the planet. He once started to write a book entitled How to Live to 150. He was an early adopter of aerobics in the 1970s and he has kept tabs on his weight and exercise ever since.

But don't imagine that Clements has lived an ascetic life. He has dropped acid, smoked dope, taken speed and, terrifyingly, "all the other stuff". He lived with 100 others in a commune in central London and was one-third of a menage a trois. He once worked for the European Space Agency, but quit to become a house-husband and look after his son.

Oh yes and he should be dead. On 15 October 2007, Clements went to his doctor for a routine prostate examination; he was almost halfway through his projected century and a half, so a check-up seemed sensible. It emerged that his prostate was fine, but his bladder was not. Two days later, he was under the knife: he had stage three cancer and it was metastatic – aggressive and with the expansionist tendencies of a biological Napoleon. His urologist told him he had a month or two to live. Clements sought a second opinion, then a third, but they all said that same thing. He moved into a hospice to die.

Did the diagnosis come as a shock? "You're fucking right," he says, with a wry chuckle. "There's no bigger shock than being told you're about to die in a few weeks."

We are sitting in the cafe of the Google Campus, just off the Silicon Roundabout in east London, and Clements is drinking herbal tea. He has cropped silver hair and a tidy beard; he wears rimless glasses and is dressed smartly all in black, apart from incongruous adventure sandals ("I get hot feet"). He could easily pass for 15 years younger than his actual age.

Clements would tell you that the reason he's alive today is because of far-reaching experiments he has conducted on himself since 2007. He measures, by his estimation, several hundred aspects of his lifestyle – "biomarkers" is the technical term – every day. Some of these are pretty straightforward (weight, body composition, muscle mass) while others are more sophisticated (urine pH).

He notes every mouthful of food that passes his lips and he has tried 140 supplements, but settled on about a dozen that he takes regularly. All of these results are eventually uploaded to a spreadsheet, which is now "a million cells". As a retired electronics engineer and self-styled "nerd", he is drawn to number-crunching.

Clements's doctors were not exactly opposed to what he was doing – they just thought he was wasting his time. "The consultants were… I won't say against it, but indifferent," he says. "They said, 'You've got metastatic cancer. There's no point doing these biomarkers, they'll only tell you that you've got it.' And I said, 'But won't they say how badly I've got it?' And they said, 'It doesn't matter. You've got it.' "

These days, Clements is so in thrall to his research that if he feels fine, but his data suggests he has taken a downturn, he is more inclined to believe the data.

Clements began conducting his experiments in isolation, but he was far from alone. In fact, weren't we all embracing our inner geeks? In 2006, Nike introduced its Nike+ personal speedometers, where a sensor embedded in your shoe would calculate how far and how fast you had run.

If you did well, Paula Radcliffe might chip in to tell you, through your earphones, that you had smashed your personal best. Nintendo Wii Fit was launched in 2007 and encouraged you to compete against friends and family in "body tests" with the goal of increasing your "Wii Fit age". It has sold nearly 23m units.

It was not just outliers and tech heads, either. If you have ever stepped on a set of weighing scales then you have participated in self-analysis. If you have worked out how much money goes out of your bank account each week, likewise. The ability to chart your progress towards a designated goal is seen as essential to success in business, politics, medicine and sport.

It's just that previously we had never been able to expose our personal lives to the same scrutiny. This changed with the spread of the smartphone and in particular the Apple iPhone in 2007; now, many of us own sophisticated and ever-present devices for monitoring our personal improvement.

The first people to recognise and codify what was happening were a pair of Wired magazine journalists from the Bay Area in California, Gary Wolf and Kevin Kelly. They called it "self-tracking" and in 2007 founded a blog named the Quantified Self. They wanted to create an informal support group for people such as Clements (the "extreme experimenters") and for curious individuals interested in self-improvement (for example, a friend of theirs who was investigating the connection between caffeine and productivity).

The name subtly referenced the fact that previously, whenever people had looked for solutions to their problems, we tended to favour talking cures. Now was the moment for people who believed that the key to self-knowledge could lie in the collection and study of numbers.

Five years on, there are Quantified Self meetings in more than 50 cities worldwide. London's group was established in September 2010 and it follows the US model of show and tell, with presentations of around 15 minutes.

"Quantified Self is individual-driven, it's not institutional, it's not a business," explains Adriana Lukas, founder of the London group. "It's just a bunch of people trying to solve their problems."

Fifteen people attended that first meeting in London and one of the speakers was Jon Cousins. Like Clements, Cousins, a former advertising executive in his early 50s, was driven to the collection of information by desperation. In 2007, he was diagnosed with bipolar disorder.

A psychiatrist asked him to track his up and downs; Cousins looked into existing systems, but ended up devising his own, based around a set of playing cards. He liked the cards, because he felt less self-conscious sitting in a coffee shop with them than he did writing in a journal or answering a questionnaire.

Each day, the cards produced a "happiness number", which he logged on a graph. Crucially, this score would be shared with some of his friends by email. If it was particularly low, they might ask why or send encouragement. Cousins found, almost instantly, that his depression was alleviated – his graph no longer spiked so violently and the line showed a consistent upward profile. His system worked for him and, through word of mouth, others found it helpful too; Moodscope, which is free or available as a paid premium version, now has 33,000 members. In a recent Department of Health public vote, it was the runaway winner as favourite health app.

"I got goose bumps hearing Jon speak," remembers Lukas. "I was thinking, Quantified Self could be huge! You just get that feeling. Fifteen people sitting in a seminar room, it doesn't look that way, but people were doing these amazing experiments. And if some people do it, more people will do it."

Quantified Self could be on the cusp of tipping now in the UK. At the last London meeting, in October, at the Google Campus, there was a capacity crowd of 130 and another 30 people on the waiting list. The speakers were often wacky, but never boring. Dr Ryota Kanai, a cognitive neuroscientist at the University of Sussex, gave a presentation on what he had gleaned from studying hundreds of MRI scans of his own brain. Jules Goldberg explained how his wife's complaints about his snoring led him to develop an iPhone app, SnoreLab, which allows you to test the efficacy of snoring remedies.

The audience was a mix of old-school pioneers, such as Clements and Cousins, and young, smart chic-geeks. At the pub afterwards, there was an excited chatter about the latest sleep monitors, tools for measuring oxygen saturation and "sexy" glucose meters. Everyone had their own reason for being there – typically a variant on wanting to live the longest, happiest life possible – and they were hoping to pick up some tips for their quest.

"The goal isn't to figure out something about human beings generally but to discover something about yourself," Gary Wolf once wrote. "Their validity may be narrow, but it is beautifully relevant."

Also, it starts narrow, but who knows how wide it can get? While individuals may not have the analytic skills or medical knowledge necessary to make reliable discoveries, if thousands of app users are creating data, scientists may be able to detect patterns that suggest more well-founded relationships between an input and an output.

In 2008, CureTogether was launched to help individuals who live with chronic pain; it quickly found an audience and it now has more than 25,000 members who have shared data on 576 medical conditions – from which anxiety treatments work best (exercise, Xanax, yoga and spending time with animals) to how best to deal with migraines (find a dark room with no noise, avoid triggers such as red wine and MSG).

In July, it was bought by 23andMe, a biotechnology company co-founded by Anne Wojcicki, the wife of Google co-founder Sergey Brin. This type of data does come with caveats. It hasn't been subject to the randomisation and double-blinding of clinical trials, and we also need to be aware of placebo effects – patients may find it hard to decipher whether it is a treatment or their predictions about a treatment that is changing their condition. Yet such crowd-sourcing websites – PatientsLikeMe is another – are beginning to yield results that the mainstream medical community could find useful.

Self-tracking will never be for everyone. Alexandra Carmichael is the current director of the Quantified Self in the US and a founder of CureTogether, but she proves that the path to self-improvement can be a challenging one. For almost two years, she tracked 40 different streams of personal data, but then, in April 2010, she quit tracking because of the strangling pressure it was exerting.

"Each day, my self-worth was tied to the data," she wrote. "One pound heavier this morning? You're fat. Skipped a day of running? You're lazy. I won't let it be an instrument of self-torture anymore."

For individuals such as Clements, there is reassurance and some camaraderie from the regular meetings. But as he talks about his routine of testing and searching for patterns, which sometimes occupies him for 18 hours a day, you sense that for some self-tracking is most valuable not for its results, but as a focus and welcome distraction.

"Luckily, I like doing it," he says. "It's given me something to do for five years. And I think I'm on to something. It gives me optimism."